1. Field of the Invention
This invention relates to a method for utilizing a plasma reaction under atmospheric pressure, and more particularly to a method for utilizing plasma reaction under the atmospheric pressure which can apply an anticorrosive effect to surfaces of pigment, dye, and cement powders by treating with high efficiency the surfaces thereof by utilizing a highly stabilized glow discharge plasma under atmospheric pressure.
2. Statement of the Prior Art
In general, a plasma is in a high ionization state of ions and electrons and thus in a neutral state. It is well known that such plasma is different from a neutral gas. This plasma can be artificially obtained by a gaseous discharge.
A film forming method and a surface improving method which utilize a low pressure glow discharge plasma have been generally known in art of application, and such methods have been applied in various industrial fields. One of the surface treatment methods utilizing the low pressure glow discharge plasma is the so-called organic plasma method which can effect thin film forming and surface treatment by forming an organic compound gas into a plasma. Further methods for producing a diamond powder and a super-fine powder or a method for surface improvement utilizing plasma in a vacuum chamber have been proposed.
However, in such a conventional surface treating method utilizing the low pressure glow discharge plasma, disadvantages are that a low pressure vacuum device or equipment is required on account of a reaction under a vacuum of 10.sup.-5 to 10.sup.-3 Torr, and a long time and high cost are required for production due to a discontinuous treatment (batch treatment).
Further drawbacks are that the equipment, treating time, and treating processes become substantially complicated and an additional step for treating a waste fluid is required, since in the surface treating method by means of the powder or the like, it is necessary to treat the surfaces of the pigment or the like in a wet process with a resin, various acids, alkalies, aerosol containing a surface active agent solution and the like, and to dry, grinding, and classification.
Heretofore, various methods for achieving the anticorrosive effect have been proposed.
(a) Descaling operation
Mechanical operation: improvement of metal itself, special chemical treatment, electrical treatment, forming of passive state compounds and the like; PA1 Chemical operation: pickling (nitric acid, hydrochloric acid, phosphoric acid); PA1 Blasting treatment, removing treatment of rubbishes, dusts, salts, acid vapors; PA1 Use of poisonous pigment (lead, mercury, arsenic); PA1 Anticorrosive paints, painting treatment (under coat, intermediate coat, top coat treatment).
(b) Surface preparation
(c) Anticorrosive operation
There are problems of poisoning due to dangers of intoxication by poisonous metals and solvents or dangers due to dust in the above operations. Further, the anticorrosive painting treatment requires an under coating. However, the middle painting and upper painting require various limitations and complicated steps. The pigment, metal powders, and the like are used as the paints. In particular, a white pigment and the like are subjected to treatment with acids such as hydrochloric acid or sulfuric acid to increase a whiteness degree. Also, an organic acid treatment is carried out to increase dispersion of the pigment. However, these treatments have an adverse effect in preventing corrosion.